Climate Change, Heat Waves, and Adaptation

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

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The main idea, as it is portrayed, driving the Obama administration’s pursuit of carbon dioxide regulations is that climate change is leading to all manner of bad things. Pointing to concrete example of bad things that have resulted from human greenhouse gas emissions, however, is much more challenging than just saying it is the case. In fact, for most climate/weather events and their resulting effect, the bulk of the science contradicts the administration’s contentions.

Roger Pielke Jr. makes it a habit to point out how White House proclamations concerning extreme weather events go awry. We have similar habits.

An especially egregious example concerns heat-related mortality. It is true that extreme heat can lead to excess mortality. It is also true that global warming should lead to more heat waves. However, it is NOT true that global warming will lead to more heat-related mortality—the logic forwarded by the administration. Frequent readers of this blog are well aware of this.

However, as not everyone (to his or her detriment) is a frequent reader of this blog, we presented our findings on climate change and heat-related mortality to the audience at a science policy conference held by the American Geophysical Union (AGU) this week. Our conclusions were:

The cause of the observed decline in the sensitivity to extreme heat in the face of rising heat is likely found in a collection of adaptations including increased access to air-conditioning, better medical care, improved building design, community response programs, heat watch/warning systems, and biophysical changes. There is no reason to think that such response measures won’t continue to exist and be improved upon into the future.

In our recent study summarizing the findings on declining heat-related mortality trends in both the U.S and Europe, we made this observation (Knappenberger et al., 2014):

“Some portion of this response [the declining sensitivity to excessive heat events] probably reflects the temporal increase in the frequency of extreme-heat events, an increase that elevates public consciousness and spurs adaptive response. In this manner, climate change itself leads to adaptation.”

It is insufficient and inappropriate to ignore this effect when compiling and discussing the impacts of climate change. If an increasing frequency of heat events raises public awareness and gives rise to an adaptive response that lowers the population’s relative risk due to extreme heat, this must be properly weighed against any increases in mortality that result from a greater number of mortality-inducing heat events.

Our analysis highlights one of the many often overlooked intricacies of the human response to climate change.

Our full AGU poster, “Climate Change, Heat Waves, and Adaptation,” is available for viewing online here.

Hopefully, it opened some eyes.